Electrolyzed sterilizing water has sterilizing power and disinfecting power against various kinds of bacteria, fungi, viruses, and the like, and examples thereof may be hypochlorous acid or sodium hypochlorite.
Hypochlorous acid is a chlorine-based disinfectant, and a strong oxidant.
The sterilizing power and disinfecting power of the chlorine-based disinfectant are determined by free residual chlorine. The free residual chlorine is present as Cl2(aq), hypochlorous acid (HOCl), and a chlorite ion (OCl−), and is present in a different existence form depending on pH.
The free residual chlorine is present in a form of chlorine gas (Cl2) in pH 4 or lower, in a form of hypochlorous acid (HOCl) in weak acid and neutral zones, and in a form of chlorite ion (OCl−) for an alkaline zone. The sterilizing power of the hypochlorous acid (HOCl) is known to be stronger than that of the chlorite ion (OCl−).
The hypochlorous acid water is classified into strong acid type hypochlorous acid water (pH 2.7 or lower, concentration of available chlorine: 20˜60 ppm) and weak acid type hypochlorous acid (pH 5.0˜6.5, concentration of available chlorine: 10˜30 ppm). In view of stability of the available chlorine, the weak acid type hypochlorous acid water is excellent.
In the related art, Korean Patent Registration No. 10-0634889 of the present applicant discloses a method for preparing sodium hypochlorite water.
According to the method, raw water containing a predetermined concentration of salt water is fed into a diaphragm electrolytic bath having a diaphragm disposed between a positive electrode and a negative electrode, and a direct current is applied to the positive electrode and the negative electrode, to thereby conduct electrolysis. Then, at the positive electrode, chlorine ions (Cl−) dissociated from the raw water are oxidized to generate chlorine (Cl2(aq)), which then reacts with the raw water to thereby generate a high concentration of hypochlorous acid water (NaOCl). At the negative electrode, sodium ions (Na+) are reduced to react with the raw water, to thereby generate strong alkaline water (This constitution has been made by the inventors of the present application).
As another related art, there is a method for preparing weak acid type hypochlorous acid water by electrolyzing raw water added with 2˜6% hydrochloric acid in a non-diaphragm electrolytic bath.
According to the method, chlorine ions (Cl−) are oxidized to generate chlorine (Cl2(g)), and the chlorine (Cl2(g)) reacts with raw water (H2O) to generate hypochlorous acid (HOCl), which is then mixed and diluted with a large amount of raw water to prepare weak acid type hypochlorous acid water of pH 5.0˜6.5.
However, the apparatus for preparing hypochlorous acid water or sodium hypochlorite of the related art has a problem in that a low mixing degree of an electrolysis product, such as a high concentration of hypochlorous acid or sodium hypochlorite, and raw water results in insoluble chlorine (Cl2(g)), which causes the deterioration in efficiency of preparing electrolyzed water.
Moreover, when the insoluble chlorine is used as electrolyzed sterilizing water, it remains on an object to be disinfected and thus causes deformation or spots on the object to be disinfected.
Moreover, the apparatus for preparing hypochlorous acid water or sodium hypochlorite of the related art requires a separate mixing and diluting bath for mixing the electrolysis product generated in the electrolytic bath with raw water therein, a valve for controlling the inflow of the raw water fed into the mixing and diluting bath, a separate water conduit for discharging the electrolyzed sterilizing water generated from the mixing and diluting bath, and the like, and thus the apparatus inevitably becomes more complicated and bigger.